The Secret Flavor: Umami


Sweet, salt, sour and bitter. These are the four familiar tastes we’ve come to know best. And then there’s another flavor—umami. Until recently, we weren’t sure how to name this fifth flavor, much less describe it. But that hasn’t stopped us from craving it and creating it for most of culinary history.

Years ago, a houseguest offered to make a simple pasta sauce for dinner. She sautéed onion, garlic and red pepper in extra-virgin olive oil and threw in handfuls of chopped tomatoes, just as I would have done. Then she surprised me by finishing off the sauce with a tablespoon or two of soy sauce. “Pumps up the flavor,” she declared.

Ever since, I’ve dribbled soy sauce over my tomato-based pasta sauce whenever I discovered that I didn’t have any Parmigiano-Reggiano cheese to grate on top. I always assumed that both the soy sauce and the cheese added flavor because they were vehicles for salt, even though adding table salt didn’t achieve the same effect.

Now I know better. The soy sauce and the Parmigiano-Reggiano cheese transformed my meals from wan to wonderful, not because of their salt content, but because both are powerhouse purveyors of something called “umami.”

Identified by a team of University of Miami researchers in 1996, umami is our fifth taste — the long-lost counterpart of four other tastes with which we are far more familiar, namely: sweet, salt, sour and bitter. Since the research team published their findings in 2000, umami has seized the interest of other scientists, health professionals, food manufacturers and chefs around the world.

Many people struggle to define umami, often calling it “savory,” “meaty” or “rich.” They try to explain it by referring to dishes in which umami is the star performer: a golden chicken soup, roasted shiitake mushrooms or navy beans simmered with the bone of a well-cured ham. Even though it wouldn’t be any easier to describe “salt” or “sweet” without referring to the way those tastes are represented in certain foods, umami comes off as somehow more exotic. That explains why some consumers are compelled and others leery about the sudden wave of interest in all things umami.

“Some people think of umami as a newfangled, overly scientific term that they don’t need,” says Fuchsia Dunlop, author of Land of Plenty (W. W. Norton, 2003) — a Sichuan cookbook — and an expert on both cooking and current events in China. “But I think it’s tremendously useful because it explains so much of what we already know about traditional cooking. We’re just using the Japanese word for it. That makes it sound foreign, but it’s not foreign at all.”

Unlocking Umami Flavor

As far back as 3,000 years ago, Greeks and Romans were carefully boosting what we now know as the umami in their foods by using a condiment made from fermented fish sauce. In 1825, in his famous treatise The Physiology of Taste, French gastronome Jean Anthelme Brillat-Savarin offered the word “osmasome” for rich, meaty tastes, and he predicted that future chemists would probably figure out what triggered it. Finally, in the 20th century, Japanese chemist Kikunae Ikeda hung a lasting moniker on the taste and determined its source.

In 1908, Ikeda began trying to replicate the flavor of a traditional soup he made from boiled kombu (one of the sea vegetables often called seaweed) and dried tuna. He mixed together salt, sweet, bitter and sour, but it was something altogether different. In his lab, he finally managed to isolate the substance that gave the broth its distinctive taste: glutamate, the most plentiful of the 20 amino acids that make up proteins. Ikeda named the taste of glutamate “umami,” most simply translated as “delicious.” (The flavor enhancer monosodium glutamate, or MSG, is the sodium salt of glutamate. Comprising water, sodium and glutamate, MSG acts on the same receptors as glutamate. For more, see “MSG: Umami Imposter?” below.)

Other scientists soon built upon Ikeda’s discovery with new revelations. Not only do other amino acids also trigger this deliciousness, but there is also a second group of compounds that build the umami effect. These are nucleotides, the molecular building blocks of RNA and DNA, found in a wide range of foods, including shellfish, pork and mushrooms. They impart some umami on their own, but more important, they magnify the umami of foods rich in glutamates and other amino acids — foods like chicken, tomatoes, aged cheeses, fresh corn and almonds. When nucleotide-rich foods are added to foods rich in amino acids, the result is a flavorful synergy that heightens the umami drama.

“That’s the key to umami cooking,” says chef David Kasabian, coauthor with his wife, Anna, of The Fifth Taste: Cooking with Umami (Universe, 2005), a virtual umami bible with scientific explanations, recipes from America’s top chefs, and the Kasabians’ own umami-accelerated versions of classics like meatloaf and chicken in wine. “When you put the basic umami and the synergizing umami together, the effect isn’t just additive — it’s multiplied. A basic tomato sauce has lots of umami, but when you add mushrooms, it has considerably more.”

The Evolution of Umami

Over the course of the past decade, scientists have discovered receptors housed in our taste buds that respond specifically to umami, just as there are receptors for sweet, salt, sour and bitter. When these umami receptors bind to glutamates and certain other amino acids and nucleotides, they send a signal to the brain. That signal combines with signals triggered by savory aromas to create a highly pleasant sensation concentrated in the orbitofrontal cortex, the section of the brain right above the eyes.

“Umami is a separate taste quality mediated by separate receptors,” explains Sue Kinnamon, PhD, a researcher at the University of Colorado, Denver, who studies taste mechanisms. “And we like the taste. It’s a savory, yummy quality.”

The fact that our bodies are designed to recognize and enjoy umami tells us that foods with naturally occurring umami are good for us. “There aren’t that many taste receptors in the mouth, so one has to assume that there’s a long-term biological interest in detecting umami,” says Gary Beauchamp, PhD, director of the Monell Chemical Senses Center at the University of Pennsylvania.

Our sense of taste is a highly evolved mechanism that signals what we should and should not eat. All humans respond positively to the taste of sweets because sweet foods are a reliable source of calories. We may wish we could turn off this particular mechanism when coworkers leave a platter of brownies near the coffee maker, but our foraging forebears relied on the instinctual preference for sweets to identify good sources of food energy.

We respond positively to the taste for salt because it contains minerals that help our bodies maintain a proper electrolyte balance.

We respond negatively — at least as infants — to bitter and sour, because those tastes warned early humans that something might be poisonous, unripe or spoiled. As adults, most of us enjoy bitter and sour flavors in small quantities that help heighten or highlight other flavors and aromas.

Many researchers now believe that humans developed a taste for umami because it signals the presence of protein. The foods packing the greatest umami punch are the ones that provide proteins broken down into free amino acids. These “free” glutamates and other amino acids are created by fermenting, aging, toasting, roasting, brazing, stewing — any process that breaks complete proteins into their constituent parts.

Thus, an aged steak has more umami than a fresh one; raw eggs have umami but considerably more when cooked; winter squash goes wild with umami when slowly roasted. But some foods such as corn and peas are packed with umami when fresh. (For more foods teeming with umami, see “Umami Shopping List,” below.)

When we eat whole proteins, our digestive systems burn a lot of energy breaking them down into amino acids. The amino acids in umami-rich foods are already in a free state, so they are more quickly and easily digested than complete proteins. As the Kasabians put it, “Umami is the taste of amino acids that are ready for our bodies to use.” The free glutamates are immediately put to work in the intestines, where they fuel the overall digestive process.

Umami Satisfies

Understanding these umami mechanisms isn’t just interesting — it’s useful, says Edmund Rolls, DSc, a professor at the Oxford Centre for Computational Neuroscience, who researches taste mechanisms and the brain. “Many people are interested in knowing what makes food palatable,” says Rolls, in part because this helps “promote the eating of good food at the expense of unhealthy foods.”

Understanding the science of cuisine is important in this regard, he explains, because it helps us develop food preparations that are appropriate. “For instance,” he says “some people don’t like the taste of nutritionally good foods like green vegetables, but you can enhance the flavor of these foods by adding umami.”

By choosing foods that taste good — and understanding how to make them taste even better — we’re simply relying on the body’s basic wisdom to maintain a balanced diet and a healthy weight. Jacqueline Marcus, RD, a nutritionist who practices in Northfield, Ill., points out that we are born with basic instincts telling us which foods are good for us and how much we need to eat of them. Just watch how a baby gulps umami-rich breast milk, then pushes away from the mother when full.

“The umami taste helps provide you with the sensation of being fed,” says Marcus, who’s been researching and working with umami for 12 years. “That’s essential in weight management. A little bit of foods with the umami taste is satisfying to the palate and satiety, or fullness.”

In a culture looking for ways to amplify eating pleasures without amplifying its already significant weight problems, that’s umami wisdom worth trying.

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Kristin Ohlson is a writer in Cleveland Heights, Ohio.

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By Kristin Ohlson